Existing subscriber identity module (Subscriber Identity Module, SIM) cards are categorized into two types: integrated circuit (Integrated Circuit, IC) SIM cards and chip SIM cards.
An IC SIM card is a chip provided with a microprocessor, and five functional modules are installed inside. These functional modules are adhesively sealed behind a copper contact of the SIM card and packaged in a manner the same as a packaging manner of a common IC card. The packaging manner of a common IC card is embedding a microelectronic chip into an international standard-compliant substrate to form a card. After the packaging is completed, the SIM card is inserted into a card connector of a terminal, and a user may insert, remove, or replace the SIM card according to an actual requirement. This type of SIM card is usually made of plastics or common metallic copper. Therefore, a surface of this type of SIM card is liable to deformation at a high temperature. A deformed SIM card affects normal use by a user. A tolerable temperature range for this type of SIM card is: −25° C. to 70° C.
The IC SIM card can tolerate a narrow operating temperature range, and requirements for its application in industrial devices and in-vehicle devices cannot be met. Therefore, chip SIM cards have emerged. In this type of SIM card, five modules of an IC SIM card are packaged inside a chip, so that its reliability is higher and its tolerable temperature range is relatively wider. Normally, the temperature specification is: −40° C. to 85° C.
The IC SIM card and the chip SIM card are consistent in their external pin functions and time sequence requirements, only different in their packaging forms. Main external pins are VCC, RST, IO, CLK, VPP, and GND. A level range is between 1.8 V and 5 V (including 1.8 V and 5V). Currently, most SIM cards have a level of 1.8 V, and have a relatively strict requirement for a power-on time sequence.
A transmission distance of an original signal outputted by a SIM card is short. According to analysis of wiring emulation on a printed circuit board (Printed Circuit Board, PCB), generally, a wiring length for the original signal outputted by the SIM card should not exceed 25 cm. If this distance is exceeded, a problem that the SIM card signal cannot be read may occur probabilistically. Therefore, a SIM card is generally placed directly in a device for use.
However, a SIM card cannot be directly placed in a device in some applications that require the SIM card to be placed far away from the device. For example, (1) in an in-vehicle entertainment system, some types of vehicles require that a SIM card be placed far away from a main communications system of the vehicle; (2) in an industrial communications module, because of a high ambient temperature, a SIM card needs to be kept far away from a terminal device, so as to avoid a failure of the SIM card due to deformation after long-time exposure to a high temperature. Yet if the SIM card is placed far away from the device, the current transmission distance of an original signal outputted by the SIM card cannot satisfy these applications.
Therefore, it is necessary to provide a method to resolve the foregoing problem.